With the Carat 840 and the Carat 920, Bühler from Uzwil is further expanding its range of die casting solutions, in response to the increasing demand from the automotive industry for machines to produce ever larger components. These die cast machines are the most powerful of their kind in the world, featuring critical fluid power technology — hydraulic accumulator systems from Roth Hydraulics in Biedenkopf enable high component quality and ensure reliable and energy-efficient casting forces for the machine.
Automobile manufacturers are breaking new ground in their production processes with high clamping forces required for the manufacture of large-format and complex aluminium components for car bodies, for example to produce front or rear underbodies for vehicles. The new Carat 840 and Carat 920 die casting machines from Bühler make such production solutions possible. The central component here is an extremely powerful and precise injection unit with uniform clamping force application. To reliably meet this requirement, Bühler decided to use a pressure accumulator system from Roth Hydraulics. It is the drive of the casting unit, which decisively generates the component quality and ensures a permanently reliable performance.
The demands on the accumulator system are many-sided: on the one hand, the new solutions require a larger amount of stored energy and, on the other hand, an extremely fast power development in order to ensure the necessary dynamics of the injection unit. The Carat 920 casting unit, for example, develops 2130 KN of dynamic casting force and 5340 KN of solidification pressure. The special challenge here is to enable around 1.5 m of piston stroke within 100 msec in the second phase of the casting process. The acceleration of the entire system including liquid aluminum is practically from zero.
“The Carat 920 can inject more than 200 kg of liquid aluminum into a mould within milliseconds. In doing so, it holds the mould together with a force of 92000 KN. That’s as if the entire Eiffel Tower, with its weight of around 9,000 tons, was pressing on the mould,” explained Michael Cinelli, Product Manager Bühler Die Casting. The Roth Hydraulics hydraulic accumulator manages this production task with ease and high precision.
To achieve such solutions, the experts from Bühler and Roth Hydraulics have been cooperating for many years. Cinelli emphasised, “The many years of cooperation in component development with Roth has always made it possible to quickly develop new solutions and further develop existing technology. The joint focus is always on the end customer and the required reliability of the components.”
The largest die casting machines in the Carat series are as big as a house. They are 8 m high and stand on a floor space of around 100 m2. In addition, the Carat’s two-platen technology features a patented and stiffness-optimized platen design for uniform clamping force application, ensuring minimal platen deflection and high dimensional accuracy of castings. In combination with Bühler’s unique real-time controlled casting unit and DataView control, the Carat offers the highest casting dynamics and quality.
The enormous power density of hydro storage systems as well as the precise release of energy in the right quantity and at the required time in die casting production saves electrical energy and significantly reduces the required connection power. In addition, the use of recycled aluminum or aluminum obtained through renewable energies enables the potential of CO2-neutral production. As a component of the entire production chain, this improves the ecological footprint of the end product, in this case of the vehicle.
Bühler’s vision for the future of the die casting industry is 0% scrap, 40% less cycle time and 24/7 availability. The larger the castings, the greater the leverage for reducing production costs by reducing cycle time, scrap and increasing availability. Bühler is a pioneer with machines for the production of large die-cast parts and the world market leader in this segment. The Roth family company is also a world market leader in the segments of energy storage systems, composite technologies and surface heating and cooling systems.
According to Frank Fuchs, Managing Director of Roth Hydraulics, “Family-run companies pursue similar values and focus on personal customer relationships. We are pleased and proud that we have been cooperating with Bühler on this basis for many years. The use of our hydraulic accumulators in the new Carat range underpins our successful partnership.”
Roth Hydraulics offers energy-efficient hydraulic accumulator solutions for technologies where hydraulic energy needs to be stored or converted. The fluid technology components are not only used in die-casting machines, but also in energy and power plant technology, mobile hydraulics or in oil and gas technology. As a full-range supplier, Roth Hydraulics provides a complete technology range with piston, bladder and diaphragm accumulators as well as accumulator systems for a wide variety of applications. Roth storage systems are designed according to a modular principle. Depending on the requirements, the manufacturer implements customized and economical solutions, as in this case for the family-owned company Bühler.
Filed Under: Accumulators